In a mobile satellite communication system, circularly polarized antennas having high gain characteristics in an elevation angle direction and non-directional characteristics in an azimuth direction are required to be terminal antennas mounted in a terrestrial moving terminal. A cross-dipole quadrifilar helix antenna has been commonly used for the purpose of being utilized as a non-directional circularly polarized antenna in the azimuth direction.
However, since the structure of such a cross-dipole quadrifilar helix antenna has high profile characteristics, it is not appropriate for an antenna structure to be mounted in the terrestrial mobile terminal. In addition, when the mobile terminal is on the move, an elevation angle direction between the antenna and a satellite object (or a target) is changed depending on the pitch of a road or a change in a latitude to result in a lower radiation pattern performance of the antenna in the mobile terminal to degrade link characteristics in a mobile wireless communication system or mobile broadcast system.